The present invention relates to apparatus for longitudinally slitting moving webs of material, such as synthetic resinous films and the like, to form a plurality of strips or sub-webs. More particularly, the present invention relates to slitting mechanisms especially adapted for use with such apparatus.
Relatively thin sheet materials such as synthetic resinous film, foil, paper, laminate and cloth, are typically manufactured in the form of wide, long webs. Such webs may measure, for example, 6 feet in width by 1,000 feet in length. Each web is usually wound about an elongate cylindrical supply core into a roll for transport and storage. The manufacturer of consumer products from such webs, for example, rolls of synthetic resinous film, usually involves use of an apparatus known as a slitter/rewinder. An apparatus of this character is disclosed in U.S. Pat. No. 2,769,600 to Kwitek et al.
An apparatus for longitudinally slitting moving webs of material typically comprises: (a) a frame means for rotatably supporting, about a first fixed axis, a rolled web of material to be slit; (b) one or more cutting devices, or slitting mechanisms, for slitting the web into a plurality of strips, said devices being disposed adjacent the web of material; (c) a take-up means for winding into individual rolls, strips of material formed by slitting the web of material; and (d) means for guiding the web of material in a path which extends from said support means to said take-up means. The cutting devices are suitably mounted on a support mandrel. The support mandrel is suitably rotatable from a first position wherein the cutting devices, or slitter blade carriers, are disposed adjacent the path of the web to a second position wherein said blade carriers are disposed remote from the path of the web.
In slitting a web of material, a number of cutting devices, or slitting mechanisms, are known. Such devices include knives, scissors, shears and the like. With one device, a web is slit by a cutting wheel bearing on a mandrel. With another device, the web is slit by a blade which bears on a shallow groove formed in the surface of a mandrel over which the web to be cut travels. With still another device, the web is slit by mating sets of blades which bear against each other. All of such devices employ one or more sharp cutting edges to slit the material. These sharp cutting edges are hazardous to an operator or a user. An operator may be exposed to said cutting edges during initial installation of a cutting device into an apparatus for slitting moving webs of material. In addition, cutting edges tend to become dull over time and must either be sharpened or replaced. As such, an operator is exposed to said cutting edges during removal of a cutting device for sharpening or replacement and during reinstallation of said cutting device. More importantly, an operator may be working near the cutting device while performing maintenance on the apparatus. If the cutting edges are not adequately guarded, an operator might easily come in contact with one or more edges, thereby receiving an injury.